Referring to FIG. 4, a prior art air inflation cushion is illustrated. The air inflation cushion includes the following elements. A lower sheet is included. An upper cushion portion is adhered upon the lower sheet. The upper cushion portion includes at least one air inflation cell. Each air inflation cell has an approximate rectangular cross section and is supported by four cambered edges for enhancing the structure of the cell. The four edges divide the air inflation cell into four lateral surfaces. If the number of the cell is greater than two, then the cell is extended with a communication trench which causes two adjacent cells are communicated to one another. An air tap is at one of the cells and extends from one of the helical edges. Preferably the air tap is inclined to a lower seat of the upper cushion portion and the opening of the air tap faces upwards.
However, in the above mentioned prior art, in venting air, the cambered edges can not make air within the cushion completely vent out due to the design of the cambered edges. When the cells are inflated, the cells are expanded so that the cells are in contact with each other and thus airflow is low and the skin of the body can not be cleaned effectively. Thus for a long time, the user easily gets bedsore, or other skin diseases. Furthermore the cambered edges of the cells make the cushion being soft and thus the user's pose is affected, even the user will feel unstably as sits or lies upon the cushion. As the cushion is used for a long time, the circulation of blood is not good and thus the health of the user will be affected.